Technical Abstract:
Geometric mean conglutinin (K) and immuno-conglutinin (IK) serum activity (methods by O. Barta & V. Barta, Zbl. Vet. Med. B, 20:57-70, 1973) were followed in 101 light-weight feeder calves on 4 Tennessee farms (FM), at an order-buyer barn (OBB) and over 4 weeks in a USDA-ARS feedyard (FY) located in Bushland, TX. Half of the calves were vaccinated for Pasteurell haemolytica A1 (Ph1). Calves were sampled on the farms, at arrival in the order-buyer barn and 4 times after shipment (days 1, 8, 15, and 28) to a feedyard (FY). After arrival at the feedyard, 73 calves developed bovine respiratory disease (BRD) within 2 weeks and were treated with antibiotics. One calf died of BRD on FY day 4. Many Ph1 (n=311) and Ph6 (n=122) were cultured from nasal turbinates and tonsil crypts. Based on farm groups, K activity of calves was significantly (P <= 0.01) different at the farm and at OBB (P <= 0.001). Significant differences were not seen for K or IK activity between sick and healthy, heifers and steers, or between Ph1 vaccinates and non-vaccinates.